Field of the Invention
This invention relates to a track wheel useful for railway cars and the like having a light-weight construction in which the wheel hub and the wheel rim are connected to one another via a double-walled wheel disc. In accordance with this invention there is provided a track wheel wherein the hub portion and the rim portion are connected together by a double-walled wheel disc, each wall of which has a cup-shaped configuration in the radial-axial plane. Each of the disc portions which form the double wall comprises a main portion to which there is integral therewith a curved transitional portion, in turn integral with a flank portion terminating in an edge. Each wall regularly passes from a central part of the wheel disc into the edges, the edge regions being supported on the hub/wheel rim or the wheel rim and being affixed thereto.
It has heretofore been proposed to provide railroad track wheels wherein the portion joining the hub and the rim comprises a multi-walled structure. The problem with track wheels having a double-walled wheel disc resides in that the connections heretofore provided for the walls to the wheel hub and particularly to the wheel rim have been inadequate. Attempts have been made to weld the walls entering substantially perpendicular into the wheel hub and the wheel rim, but practice has shown that such welding seams break, particularly in the region of the wheel rim (Hans-Kurt Obst "Die Entwicklung von Leichtradsaetzen fuer Eisenbahnwagen" 1969 in "Eisenbahntechnislhe Praxis," No. 4, October 1969).
In a known track wheel having a lightweight construction of the type described above, the outer sides of the double-walled disc have had a convex curve. Both the inner and outer regions of the disc, by which the disc is supported at the hub and the rim, have been arranged concentrically to the wheel axis as far as a narrow running conically. The welding seams in the region of the edges at the wheel hub in such a case are especially susceptible to rupture, as when the wheel is sprung the edge regions act as lever arms and load the welding seams with a radial force. Consequently, the high stress already prevailing in these regions is raised to dangerous and even breaking levels.
It has become desirable to provide a railroad track wheel having a lightweight construction having a double-walled wheel disc joining the wheel hub and the wheel rim inasmuch as such lightweight track wheels are superior to track wheels having a one-walled wheel disc, in that they can be manufactured so that the total disc thickness of the discs is smaller but the rigidity the same. It has become desirable to provide such a multi-walled wheel disc wherein the walls joining the hub and the rim can be safely secured to the hub and rim without employing a weld which will readily break under conditions of use. More particularly, it has become desirable to provide an alternate multi-walled track wheel wherein the walled disc joining the hub and the rim is replaced by a concavely shaped disc.